Alkaloids and Polyketides from Penicillium citrinum, an Endophyte Isolated from the Moroccan Plant Ceratonia siliqua

Abstract

The endophytic fungus Penicillium citrinum was isolated from a fresh stem of the Moroccan plant Ceratonia siliqua. Extracts of P. citrinum grown on rice and white bean media yielded five new compounds, namely, citriquinochroman (1), tanzawaic acids G and H (2 and 3), 6-methylcurvulinic acid (4), 8-methoxy-3,5-dimethylisoquinolin-6-ol (5), and one new natural product, 1,2,3,11b-tetrahydroquinolactacide (6), which had previously been described as a synthetic compound. In addition, 13 known compounds including seven alkaloids and six polyketides were isolated. The structures of the new compounds were unambiguously determined on the basis of one- and two-dimensional NMR spectroscopy as well as by high-resolution mass spectrometry. Citriquinochroman (1) features a new skeleton, consisting of quinolactacide and (3S)-6-hydroxy-8-methoxy-3,5-dimethylisochroman linked by a C-C bond. 1,2,3,11b-Tetrahydroquinolactacide (6) may be a biogenetic precursor of quinolactacide. Citriquinochroman (1) showed cytotoxicity against the murine lymphoma L5178Y cell line with an IC50 value of 6.1 μM, while the other compounds were inactive (IC50 >10 μM) in this assay.

Filamentous Fungi PKF121 Isolated from Dry Dipterocarp Forest Soil in Northeast Thailand Produces Antimicrobial Agents Active Aginst Methicillin-Resistant Staphylococcus aureus

“…Antimicrobial metabolites play an important role in the treatment of bacterial and fungal infectious diseases [24]. The emergence of antibiotic-resistant bacteria decreases the efficacy of therapeutic drugs [25].…”

CAROB (Ceratonia siliqua): HEALTH, MEDICINE, CHEMISTRY

“…M. El-Neketi and her colleagues have isolated and characterized six new interesting compounds, including alkaloids and polyketides from the fungi Penicillium citrinum, that grows on Carob trees in Morocco. 193 The structures of these compounds are shown in Figure 5.…”

Endophytism of Penicillium Species in Woody Plants

“…Within Penicillium, production of gibberellins has been observed by endophytic strains from herbaceous plants [60][61][62], while so far there is no direct evidence for strains recovered from trees and shrubs. Conversely, production of auxins has been reported by endophytic strains of P. glabrum [63] and P. citrinum [64], respectively from pomegranate (Punica granatum) and carob tree (Ceratonia siliqua).…”